Unger, Larry G wrote:
>
> > Jethogger wrote:
> > > Hello JOHN, Early 70's MGB head. The letter "L"
> > stamped at the rear. Had bigger valves and no water
> > return hole for the hot water chokes. Have one on
> > > my 67B I am building.
> >
> > John V. replied:
> > That's just what I was wondering. Thanks.
>
> Gents ... the early 'B'(pre 18V) cylinder heads have
> 1.58' intake valves and a 43cc combustion chamber ...
> the later 'B' (18V) cylinder heads have 1.625' intake
> valves and a 38cc combustion chamber. To produce the
> later head a larger kidney shaped combustion chamber
> was utilized, in lieu of the heart-shape of the earlier
> head, to accommodate the larger intake valve ... to
> maintain the CR the chambers were shallower and the
> thickness of the head was reduced ... the reduction in
> head thickness required that small cuts be machined in
> the top of the block to prevent the exhaust valves from
> contacting the block. *Do*not*fit*an*18V*cyl*head*to*
> *a*pre*18V*block*unless*you*have*the*appropriate*cuts*
> *machined*in*the*top*of*the*block*. Don't forget the
> differences in combustion chamber capacity as they will
> have impact on your CR.
>
> John V. ... the 1622 uses the early 'B' head.
>
> Safety Fast! ... larry.g.unger@lmco.com
> '61 MGA 1600 MkII
Larry--
Thanks again. I think I know now what I have to look for and what to
avoid. I have a possible lead on an early 70's mgb head (if the guy
decides he wants to sell it--he likes them for his race cars). Sounds
like the trick is to check the shape of the valve recesses.
The same guy also has a 5-main engine that runs (for $850 or so)--though
if I were to go that route I'd probably be better off with a 3-main 1800
for simplicity's sake.
I appreciate all your help with this.
JV
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